Show HN: We built a hidden micro-bearing system inside a 2mm ring

[spinity]

We’ve been working on a spinning ring that hides a true micro-bearing system inside a 2mm profile.

The main challenge was balancing tolerance, durability, and smooth rotation at this scale. We went through multiple prototypes dealing with ball size, raceway depth, and surface finishing before getting consistent 20s spins.

Would love feedback from anyone who’s worked on ultra-compact mechanical systems or precision manufacturing.

If you’re curious, the project is live on Kickstarter: https://www.kickstarter.com/projects/cooloze/spinitytm-beari...

[gus_massa]

I think this is not a "Show HN:" https://news.ycombinator.com/showhn.html Send an email to [e-mail] so dang/tomhow can give some advice.

How do you handle water? Can you wash the dish it? Swimming pool? Cooking bread (flour is nasty)? Oil? Direct sunlight for 4 hours?

> We went through multiple prototypes dealing with ball size, raceway depth, and surface finishing before getting consistent 20s spins.

So you have some photos or data collected during these attempts? They may be an interesting technical post. (My lab notebook was a disaster, so I don't expect a very systematic report.)

What are the materials? For some small device we had to use bronce "nuts" over aluminum threads, because apparently aluminium over aluminium get stuck too easily.)

[spinity]

First, I’d like to apologize to the community for my clumsy entrance — I probably came across like a drunk guy stumbling into a party he doesn’t yet understand. I should have spent more time learning the community norms first.

That said, let me try to respond to your very insightful and constructive questions.

At this scale, water tends to replace the air film and introduce surface tension and capillary forces between the ball and raceway. That adds drag rather than reducing friction, especially when combined with fine particles or residue. So your concern is absolutely valid.

Our honest answer is that we’re constantly balancing real-world usability against technical constraints. We did consider applying hydrophobic coatings to the raceway, but in practice those coatings wear off very quickly at the actual contact points inside the bearing, which makes them ineffective over time.

Instead, we focused on making the internal structural components corrosion-resistant and water-tolerant, and designed the system so that, rather than trying to completely block water from entering, it can be easily cleaned and quickly dried.

The “sticky” or sluggish feel water introduces in a micro-bearing is temporary. In practice, you can restore normal performance by blowing it dry with a hair dryer in about a minute.

The analogy we often use is washing your hair: if you’re not in a hurry, it will air-dry on its own. If you need to go to sleep right away, you use a hair dryer. In either case, the impact on the overall experience is minimal.

By the way give me a bit of time — I promise I’ll put together a more systematic report with photos and data from our testing. There’s no real secret sauce here, just a lot of trial, error, and tiny tolerances.

[ahazred8ta]

> We built a hidden micro-bearing system inside a 2mm ring

We don't care.

Stop spamming.